Expansion card and integrated fingerprint acquisition system

ABSTRACT

An expansion card with an integrated fingerprint acquisition system is provided that is able to be connected to a portable computer. In one aspect of the invention, PCMCIA standards are used for the expansion card. The expansion card is built such the fingerprint acquisition system is on a slidable carriage which may extend out from the expansion card housing, or may be retracted into the housing when the fingerprint acquisition system is not in use. A locking mechanism keeps the carriage in the retracted position, and a spring provides the force necessary to slide the carriage into the extended position when pressure is placed on the slidable carriage. An advantage of the invention is that the fingerprint recognition device is small enough to fit within a PCMCIA standard expansion card. Another advantage of the invention is that the fingerprint recognition system, when not in use, is enclosed within a portable computer&#39;s housing such that the invention does not use additional desk space in addition to the portable computer itself, other than that necessary for the retractable access portion to extend into an extended position.

FIELD

[0001] The present invention relates to the field of fingerprintrecognition. More particularly, the invention relates to an expansioncard with an integrated fingerprint acquisition device on a retractableaccess portion of the card.

BACKGROUND

[0002] Computer security and access is an important issue. Methods ofidentifying individuals are important to providing computer access onlyto predetermined users. Fingerprints provide a unique and absolute meansof identification that does not require remembering passwords and isalso difficult to falsify.

[0003] Electronic fingerprint acquisition systems have been introducedto eliminate the need for ink or a chemical reagent. In such systems,the subject's fingertip is pressed against or rolled over a flattransparent (e.g. glass) platen in an optical system. Light is directedthrough the platen and is reflected from the fingertip into an opticalpath including mirrors, lens and an electronic image sensor such as aCCD imager of the type employed in video cameras. The image of thefingerprint may be digitized, analyzed, printed out, stored, transmittedor compared with an existing fingerprint or fingerprints. See, forexample, U.S. Pat. No. 5,732,148, incorporated herein by reference.

[0004] A problem with existing electronic fingerprint acquisitionsystems is that they tend to be bulky and large in size. While thegeneral size of fingerprint acquisition systems has been reduced inrecent years, the size is generally prohibitive for efficient use withlaptop computers, notebook computers, or other devices with expansionslots, hereinafter referred to collectively as portable computers.

[0005] Portable computers are more limited in space than are desktopcomputers. The internal spatial restrictions of portable computers haverequired the establishment of standards for the internal accessories ofthese computers. One set of standards applicable to PC Cards, alsoreferred to as PCMCIA cards, was developed by the Personal ComputerMemory Card International Association (PCMCIA). The PCMCIA promulgatedstandards for PC Cards that are now virtually universal in the portablecomputer industry. The PCMCIA promulgated standards stating that thespatial standards for all PC Cards used in portable computers should berestricted to a rectangular space approximately 54 mm in width and 85.6mm in length. Additionally, Type I, Type II, and Type III cards wouldhave a thickness of 3.3 mm, 5 mm, and 10.5 mm, respectively.

[0006] In keeping with the PCMCIA standards for memory cards, internalmodem manufacturers have adopted the same spatial standards for use withtheir portable computer communications cards. By complying with thestandards established by the PCMCIA for memory cards, communicationscard manufacturers assured themselves compatibility and spatialconformity with computers utilizing the PCMCIA standards.

[0007] With most, if not all, new portable computers being manufacturedwith at least one PCMCIA peripheral slot, the PCMCIA specifications arenow regarded as a standard in the portable computer industry forinternal accessories.

[0008] There exists a need for a fingerprint acquisition device which iscapable of being used in conjunction with a portable computer withoutadditional space requirements. The prior art, as shown in FIG. 1, showselectronic fingerprint acquisition systems that attach to a desktop orportable computer via the serial port, the parallel port, or a UniversalSerial Bus (USB),port. These devices tend to be bulky, reside outside ofthe computer's housing, and require a lengthy cord. Further, when thesedevices are not in use, the device is still taking up often limitedspace surrounding the portable computer. An example of such a device isthe U.are.U Fingerprint Recognition System available from DigitalPersona, Inc. in Redwood City, Calif.

[0009] Users of portable computers often desire as few externalperipheral attachments as possible. External peripheral attachments takeup extra baggage space, are more easily broken and lost, and requireadditional functional space when in use. People often use portablecomputers in confined spaces, such as while seated in an airplane, thatare not conducive to the extra space required by external peripheraldevices attached to a portable computer. This is one reason for thedevelopment of standards, such as PCMCIA, for internal accessories ofportable computers.

[0010] The first PCMCIA cards developed for communication accessoriesgenerally required an intermediate cable extending from the PCMCIA card.An example is provided with respect to modems. The intermediate cable isadapted to connect between the PCMCIA card and a standard telephoneRJ-11 cable. A problem with this configuration is that if the cable isdamaged or lost, the accessory is unusable until the cable is repairedor replaced. One solution to this problem is to have a cable jack thatis extendable from the PCMCIA card, as described in U.S. Pat. Nos.5,336,099 and 5,338,210.

SUMMARY

[0011] The present invention relates to a fingerprint acquisitionsystem. More particularly, the invention relates to an expansion cardwith an integrated fingerprint acquisition device on a retractableaccess portion of the interface card. The invention provides anextension to the interface card that protrudes from the laptop computerproviding a permanent interface. That is, the portion of the interfacecard protruding from the computer provides the scanning area on which afingerprint is received. This structure eliminates the need for anintermediate cable. The extension is retractable into the interface cardwhen not in use, thereby preventing the fingerprint reader from damage.

[0012] In an exemplary embodiment, the expansion card is constructedsuch that a retractable access portion, or carriage, is able to slidablyextend out from the end of the expansion card. Constructed to fit on thecarriage, the fingerprint acquisition device has the capability ofextending from and retracting back into the expansion card housing.Thus, the fingerprint acquisition system is only exposed outside aportable computer when it is necessary to scan a fingerprint. While notin the use, the fingerprint acquisition device is retracted into theexpansion card, providing added protection for the fingerprintacquisition device from damage, and leaving more usable spacesurrounding the portable computer. When the fingerprint reader isextended outside the protective casing and exposed to human fingertouch, it may, over time, accumulate oil or foreign particles on itssurface. Addressing this concern, the invention cleans the prism surfaceas the reader is extended out from and retracted into the expansioncard.

[0013] In one embodiment, the expansion card is constructed inaccordance with PCMCIA standards, and the fingerprint acquisition deviceincludes an imaging prism, a focal lens, a redirectional prism, an imagesensing means, and a diffused light source. The fingerprint image prismis optically coupled to the focal lens, which is optically coupled to aredirectional prism. The redirectional prism is further opticallycoupled to the image sensor.

[0014] An advantage of the invention is that the fingerprint recognitiondevice is small enough to fit within a PCMCIA standard expansion card.

[0015] Another advantage of the invention is that the fingerprintrecognition system, when not in use, is enclosed within a portablecomputer's housing such that the invention does not use additional deskspace in addition to the portable computer itself, other than thatnecessary for the retractable access portion to extend into an extendedposition.

[0016] Additional advantages of the invention will become apparent uponreading the following detailed description and upon reference to thedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 depicts a prior art fingerprint acquisition systemconnected to a portable computer;

[0018]FIG. 2 depicts an exploded view of the PCMCIA fingerprint system;

[0019]FIG. 3 depicts a side view of the PCMCIA fingerprint system;

[0020]FIG. 4 depicts a top view of the fingerprint acquisition system;

[0021]FIG. 5 depicts a side view of the fingerprint acquisition system;

[0022]FIG. 6 depicts the invention in the extended position;

[0023]FIG. 7 depicts the invention in the retracted position;

[0024]FIG. 8 depicts a slidable carriage of the invention; and

[0025]FIG. 9 depicts a cleaner of the invention.

DETAILED DESCRIPTION

[0026] In an exemplary embodiment, the invention is constructed toPCMCIA standards, and is disclosed herein. It should be appreciated thatmodifications can be made which are within the scope of the invention.

[0027] The fingerprint acquisition system 30 is now described withreference to FIGS. 2-7. As shown in FIG. 2, a fingerprint acquisitiondevice 10 is housed in a slidable carriage 31. The slidable carriage iscomprised of a carriage top 31 a, a carriage bottom 31 b and an optionalcover 31 c described below. The carriage top has a central portion cutout to allow access to a fingerprint receiving portion of thefingerprint acquisition device 10. The slidable carriage 31 is extendedout from the expansion card by applying pressure on the slidablecarriage which subsequently causes pressure to be exerted by a spring45. Alternatively, the slidable carriage is retracted by applyingpressure on the slidable carriage into the expansion card. As shown inFIG. 8, when the slidable carriage is positioned as extended out fromthe expansion card, a metal wire 31 f is situated in position A of agroove 42 c. When the slidable carriage is positioned as retracted intothe expansion card, the metal wire is situated in position C of thegroove. The metal wire passes by position B of the groove when theslidable carriage is retracted or extended out. The groove 42 c extendsalong one side of the slidable carriage.

[0028] An expansion card housing comprises a sheet metal top 40, and asheet metal bottom 50. Within the housing is a case 42 comprising a casetop 42 a, a case bottom 42 b, and the groove 42 c. Also, within thehousing is contained a PC board 46, the metal wire and a spring 45. Themetal wire is attached to the case via groove 42 c and a life spring 42d. When the carriage is in the retracted position, the spring 45 is heldin a compressed state via the metal wire being situated in position C ofthe groove. When pressure is applied to the slidable carriage, thespring 45 expands, releasing the carriage from the housing. As shown inFIG. 9, when the carriage is retracted, a cleaner 44 wipes the surfaceof an imaging prism 12.

[0029] The case top 42 a and the case bottom 42 b are U-shapedstructures, such that when placed together, a channel in which thecarriage 31 slides is formed in each of the two substantially parallellateral sides. The case top 42 a and/or the case bottom 42 b areconstructed such that the carriage 31 cannot extend further than isnecessary for the fingerprint receiving portion of the fingerprintacquisition device to receive a fingerprint, and such that the end ofthe carriage 31 is at least substantially flush with the end of theexpansion card housing when the carriage is in the retracted position.The fingerprint acquisition system 30 is depicted with the carriage 31in the extended position in FIG. 6, and with the carriage in theretracted position in FIG. 7.

[0030] Centrally located between the case top and case bottom is the PCboard 46. On the end of the PC board is an expansion card connector 47that allows the expansion card to interface with a portable computer. Inone embodiment of the invention, the expansion card is a PCMCIAexpansion card, and the connector 47 is a 68-pin PCMCIA connector. Alsoconnected to the PC board is a flexible cable 34. The flexible cable isalso connected to the fingerprint acquisition device 10 through a secondconnector 24. The flexible cable is connected such that when thecarriage is extended from the housing, the flexible cable extends withthe carriage, and when the carriage is retracted in the housing, theflexible cable is retracted with the carriage.

[0031] The sheet metal top 40 and sheet metal bottom 50 comprise theouter casing of the expansion card housing. The sheet metal top and thesheet metal bottom are standard pieces known in the art. The case topand case bottom are constructed such that the PCMCIA connector isaccessible between the sheet metal top and the sheet metal bottom on theend opposite that which the carriage extends from.

[0032] In one aspect of the invention, the sheet metal bottom has anoptional cut-out portion 52 to provide extra housing space for thecarriage. This allows the fingerprint acquisition device to beconstructed thicker than it could be without the cut-out portion 52. Insuch an aspect, connected to the carriage bottom 31 b is a cover 31 c,such that when the carriage is in the extended position, the coverextends over and covers the cutout portion 52, protecting the systemfrom foreign objects entering through the cut-out portion. FIG. 3depicts a side view of the expansion card, with the cover 31 c extendingfrom the carriage. The cover may be constructed of sheet metal, or anyother material suitable to cover the cut-out portion 52.

[0033] A fingerprint acquisition device 10 that is suitable for use inthe expansion card fingerprint acquisition system is now described withreference to FIGS. 4 and 5. An imaging prism 12 is provided. Adjacent tothe imaging prism, are two diffused light sources 14 a and 14 b, such asLEDs, which are known in the art. In one aspect of the invention, onelight source may be used. The imaging prism is optically coupled to afocal lens 16, and includes an upper planar surface 12 a to receive afingerprint, and an adjacent end surface 12 b at a predeterminedcurvature and a predetermined angle to reflect the fingerprint imagetowards an exiting surface 12 c. The exiting surface is adjacent to theupper planar surface, and has a curvature such that it directs thefingerprint image towards the focal lens 16. The focal lens is opticallycoupled to a redirectional prism 18, directing a focused fingerprintimage into the redirectional prism. The redirectional prism 18 isoptically coupled to an image sensor 20, and includes an upper planarsurface 18 a, a lower planar surface 18 b, an end surface 18 c, and anentry surface 15 d. The upper and lower surfaces are substantiallyparallel to each other. The entry surface 18 d receives the focusedfingerprint image from the focal lens 16. The end surface 18 c isadjacent to the upper and lower surfaces 18 a, 18 b opposite the entrysurface 18 d and is set at a predetermined angle to reflect the focusedfingerprint image towards the upper planar surface. The upper planarsurface 18 a of the redirectional prism reflects the focused fingerprintimage towards the lower planar surface 18 b. The focused fingerprintimage passes through the lower planar surface to the image sensor 20.The image sensor 20 may be a CCD, which is known in the art. The lightpath 28 of the fingerprint image is shown in FIG. 5.

[0034] The imaging prism 12, diffused light sources 14 a and 14 b, focallens 16, redirectional prism 18, and image sensing means 20 are allcentrally located about a longitudinal axis 26. The imaging prism, theat least one diffused light source, and the image sensor are mounted ona second PC board 22. The image sensor interfaces with the second PCboard to pass fingerprint image information. The at least one lightsource also interfaces with the second PC board to receive power and/oractivation information. A connector 24 is mounted on the second PCboard, and additionally interfaces with the second PC board. Theconnector is used to transmit fingerprint image information, and toreceive power and/or activation information, to and from an externalsource. The second PC board 22 and the PC board 46 communicate via theflexible cable 34. The PC board 46 communicates with a portable computervia connector 47.

[0035] In one embodiment, where the expansion card is a PCMCIA expansioncard, the width a of the imaging prism is approximately 16 mm, and thelength c of the imaging prism is approximately 17 mm. The width e of thefocal lens is approximately 3 mm. The width of the redirectional prismis approximately 6 mm. The width g of the image sensor is approximately10 mm, and may include any housing that the image sensor is encasedwithin. The second PC board has width b, approximately 24 mm, and lengthd, approximately 32 mm. The connector 47 is a 68-pin PCMCIA connector.

[0036] An advantage of the invention is that the fingerprint recognitiondevice is small enough to fit within a PCMCIA standard expansion card.Another advantage of the invention is that the fingerprint recognitionsystem, when not in use, is enclosed within a portable computer'shousing such that the invention does not use additional desk space inaddition to the portable computer itself, other than that necessary forthe retractable access portion to extend into an extended position.

[0037] Having disclosed exemplary embodiments and the best mode,modifications and variations may be made to the disclosed embodimentswhile remaining within the scope of the present invention as defined bythe following claims.

What is claimed is:
 1. An expansion card for a portable computer with anintegrated fingerprint acquisition system comprising: a housingcomprising an upper substantially planar surface and a lowersubstantially planar surface, said upper surface substantially parallelto said lower surface; a fingerprint acquisition device inside thehousing; a retractable access portion capable of being retracted intoand extended out from the housing, said retractable access portionincludes at least a fingerprint receiving portion of the fingerprintacquisition device, such that when said retractable access portion isextended it is capable of receiving a fingerprint, and when saidretractable access portion is retracted it is at least substantiallyflush with the ends of the upper and lower planar surfaces; and aconnector adapted to interface with a portable computer.
 2. Theexpansion card of claim 1, further comprising a locking mechanism, suchthat when the retractable access portion is retracted, the lockingmechanism prevents the retractable access portion from extending intothe extended position.
 3. The expansion card of claim 1, wherein thefingerprint acquisition device comprises: an imaging prism adapted toreceive light from a light source, said imaging prism having an uppersurface adapted to receive a fingerprint, and an adjacent surfaceconfigured to reflect a fingerprint image at a predetermined angle; afocal lens to focus the fingerprint image into a focused image, saidfocal lens adapted to receive the fingerprint image from said imagingprism; a redirectional prism having substantially parallel upper andlower surfaces, and an adjacent surface configured at a secondpredetermined angle to reflect the focused image towards the uppersurface, said upper surface reflects the focused image towards the lowersurface; and an image sensor beneath the redirectional prism.
 4. Theexpansion card of claim 3, wherein the light source is a diffused lightsource.
 5. The expansion card of claim 1, wherein the card and connectorconform to the physical standards for PCMCIA expansion cards.
 6. Theexpansion card of claim. 2, wherein the locking mechanism comprises aspring, wire and groove, such that when the retractable access portionis retracted, pressure upon the slidable carriage will release saidretractable access portion to an extended position.
 7. The expansioncard of claim 2, wherein the card and connector conform to the sizestandards for PCMCIA expansion cards.
 8. The expansion card of claim 3,wherein the card and connector conform to the size standards for PCMCIAexpansion cards.
 9. The expansion card of claim 4, wherein the card andconnector conform to the size standards for PCMCIA expansion cards. 10.The expansion card of claim 6, wherein the card and connector conform tothe size standards for PCMCIA expansion cards.
 11. The expansion card ofclaim 1, further comprising a cleaner configured to clean a prismsurface when said retractable access portion is retracted.
 12. Theexpansion card of claim 11, wherein the card and connector conform tothe size standards for PCMCIA expansion cards.